This invention relates to the art of dentistry, and more particularly to a new and improved method of making a dental appliance.
The type of dental appliance with which this invention is concerned includes a plastic body portion from which an auxiliary member, such as an anchoring wire, extends. The plastic body is shaped to fit a portion, such as the palate, of a patient's mouth. The auxiliary member is secured to the plastic body of the appliance and has a portion which extends therefrom. This extending portion of the auxiliary member is shaped so as to operatively engage teeth of the patient when the appliance is positioned within the patient's mouth.
A problem in making such an appliance is the difficulty in adequately securing the auxiliary members to the body portion. One solution to this problem is set forth in U.S. Pat. No. 3,768,164 issued Oct. 30, 1973 and assigned to the assignee of the present invention. This patent discloses that a dental appliance of the foregoing type can be made by providing, at the outset of the process, a dental model formed from an impression taken from the mouth of a patient and then positioning an auxiliary member upon the model and applying a liquid material which is compatible with thermoplastic material to a selected portion of the auxiliary member. Heated thermoplastic material is then applied to the model and subsequently shaped by pressure forming to conform to the shape of the model. As a result of the shaping, the selected portion of the anchoring member is completely embedded in the plastic material. When cooled to a hardened condition, the thermoplastic material comprises the plastic body portion of the appliance and the auxiliary member is securely anchored to the body portion.
In the foregoing process, the step of applying a liquid material to a selected portion of the auxiliary member is performed in order that the plastic material surround the selected portion during the shaping of the plastic material. It would be highly desirable to provide a method of making a dental appliance of the aforedescribed type wherein the step of applying a liquid material to a selected portion of the auxiliary member is eliminated and yet the auxiliary member is suitably encapsulated by the plastic material while it is pressure formed to conform to the shape of the model.